1. Field of the Invention
The present invention relates generally to electronic lock equipment and is particularly directed to an electronic lock box of the type that contains a secure compartment for storing keys that allow entry to a structure. The invention is specifically disclosed as an electronic lock box that includes an internal movable actuator that moves in one direction to open the door to a secure compartment containing a key to the structure, and moves in the opposite direction to release a shackle that holds the lock box to the structure, such as a door handle. Much of the theory of operation of a similar movable actuator is disclosed in U.S. Pat. No. 7,086,258, by the same inventor.
In the present invention, improvements are made to the previous cost efficient design, including a more secure mechanical actuator and locking mechanisms. In addition, the present invention maximizes the “power budget” for operating the secure actuator mechanisms.
2. Description of the Related Art
In U.S. Pat. No. 7,086,258, a prime mover apparatus moves a movable actuator which engages latches that retain either a key compartment door or a shackle for attaching the lockbox to a fixed object. The prime mover typically is a high performance micro-motor with a spur gear attached which interfaces with a set of “rack” teeth that translate the rotational energy of the motor shaft into linear motion. This cost efficient design works well, however, improvements can be made.
Lockboxes require increasing levels of security as the homes they protect have increasingly valuable contents. Thieves may try multiple means at their disposal to gain entry into a lockbox so a robust latching system to thwart the would-be attacker would be a decided improvement.